1914' ColgAn. — Opislhobra?ich JF^auna of Co. Dub/in. I75 
the bod}^ of the animal being studded over witli prominent 
shortly-stalked knobs which under the microscope showed 
yellow granules within, the whole resembling copepod egg- 
sacs. The favourite food of Limapontia on the Dublin 
shores, at all events, is Cladophora rupestris. Fresh sprays 
of this weed placed with living specimens of the animal 
were observed within a few days to be completely stripped 
of their green matter, only the translucent frame-work of 
the leaves remaining. 
An examination of the radulae of 12 Dublin specimens 
showed the total number of teeth to vary from 9 to 11. 
Meyer and Mobius found the total in their largest Kieler- 
Bucht specimens 8 mm. long to vary from 16 to 18. 
Actaeonia Cocksi (Aid. and Hanc). 
A. corrugata and Cenia Cocksi (Aid. and Hanc). 
Locally abundant in rather stagnant half-tide ])0()ls, 
always on Cladophora and usually associated with Lima- 
pontia. Between October, 1907, and May, 1913, 131 
specimens were taken in 16 shore gatherings. The follow- 
ing are the details of the various gatherings : — Ten speci- 
mens at Bullock, October-November, 1907 (Colgan, '08) ; 
I at Shennicks Island, and another near Loughshinny 
(Colgan, '09) ; 8 in a pool between Dalke}^ Island and the 
Lamb, June, 1908 (Irish Naturalist, xvii., p. 164) ; 16 near 
the Martello Tower, Rush, 1910 ; 95 in 12 gatherings at 
Bullock, January, 1909 — May, 1913, from i to 35 in a 
gathering. Largest, 6 mm. long while in motion. 
The earlier gatherings at Bullock as well as those made 
at Skerries, Loughshinny and Dalkey Island were recorded 
as A. corrugata, but further study, including observation 
of the development from the egg almost up to the fully 
adult stage, has convinced me that A. corrugata is but an 
immature state of A. Cocksi. The two species of Alder 
and Hancock have accordingly been united here. They 
were described and figured simultaneously and for the first 
time in the Annals and Magazine of Natural History iox 
June, 1848, under different genera as Actaeonia corrugata 
and Cenia Cocksi. The genus Cenia was subsequently 
(1869, in Jeffreys' Brit. Conch., vol. v.) abandoned b}- Alder, 
